I have a 2001 SLK230 and I programmed my left and right buttons to open 2 garage door openers, which are both Stanley fixed code systems.

With the ignition in position 2, I held the transmitter 2 to 5 inches from the rear view mirror and pressed the garage door transmitter button and the SLK button at the same time, the indicator lamp on the SLK started flashing slowly, then rapidly. Then, I released both buttons at the same time and pressed the SLK button and the garage door opener operated.

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1993 190E 2.3
2001 SLK230
1971 LS5 (454) Corvette Convertible